V.xx
V.xx refers to various types of ITU-T communication standard. Some are for simple serial line communication (e.g. V.24, otherwise known as RS232), others are for modem communication (e.g. V.21, V.22, V.23, V.32), and others are for special uses (e.g. V.42, an error correction protocol). Sometimes, these standards are up-dated, and changed slightly, then they have bis added to the end (e.g. V.42bis a data compression protocol).

VAI: Virtual Access Interface
Virtual Access Interface (VAI) is an instance of a unique virtual interface that is created dynamically and exists temporarily. Virtual access interfaces can be created and configured differently by different applications, such as virtual profiles and virtual private dialup networks. Virtual access interfaces are cloned from virtual template interfaces.

VAN: Value-added Network
Value-added Network(VAN) is a computer network or subnetwork that transmits, receives, and stores Electronic Data Interchange (EDI) transactions on behalf of its customers.

VBR: Variable Bit Rate
Variable Bit Rate (VBR) is a QoS class defined by the ATM Forum for ATM networks. VBR is subdivided into a realtime (RT) class and non-realtime (NRT) class. VBR (RT) is used for connections in which there is a fixed timing relationship between samples. VBR (NRT) is used for connections in which there is no fixed timing relationship between samples but that still need a guaranteed QoS.

VC: Virtual Circuit
Virtual Circuit (VC) is a concept in an ATM or Frame Relay or X.25 network that represents the logical path that cells or frames travel between switches. There are two types of VCs, permenant VC (PVC) and Switched Virtual Circuit (SVC). SVCs are generally set up on a per-call basis and are disconnected when the call is terminated; however, a PVC can be established as an option to provide a dedicated circuit link between two facilities.

VCC: Virtual Channel Connection
Virtual Channel Connection(VCC), sometimes called a virtual circuit connection, is a logical circuit, made up of Virtual Channel Links (VCLs), that carries data between two end points in an ATM network.

VCD: Virtual Circuit Descriptor
Virtual Circuit Descriptor (VCD) is a unique number that identifies the permenant virtual circuit (PVC). Do not use VCD 1 or 2 because these are hard-coded for RPM management.

VCI: Virtual Channel Identifier
Virtual Channel Identifier (VCI) is a 16-bit field in the header of an ATM cell. The VCI, together with the VPI, is used to identify the next destination of a cell as it passes through a series of ATM switches on its way to its destination. ATM switches use the VPI/VCI fields to identify the next network VCL that a cell needs to transit on its way to its final destination. The function of the VCI is similar to that of the DLCI in Frame Relay.

VCL: Virtual Channel Link
Virtual Channel Link(VCL) refers to the connection between two ATM devices. A Virtual Channel Connection (VCC) is made up of one or more VCLs.

VCN: Virtual Circuit Number
Virtual Circuit Number(VCN), also known as logical channel identifier(LCI) or logical channel number(LCN), is a 12-bit field in an X.25 PLP header that identifies an X.25 virtual circuit. It allows DCE to determine how to route a packet through the X.25 network.

Vector (SNA)
In the IBM SNA, a vector refers to the data segment of an SNA message. A vector consists of a length field, a key that describe the vector type and vector-specific data.

Veronica: Very Easy Rodent-Oriented Net-wide Index to Computer Archives
Very Easy Rodent-Oriented Net-wide Index to Computer Archives (Veronica) is a search engine system for the Gopher protocol. Veronica is a constantly updated database of the names of almost every menu item on thousands of Gopher servers. The Veronica database can be searched from most major Gopher menus.

VF: Variance Factor
Variance Factor(VF) is one of three link attributes exchanged using PNNI Topology State Packet (PTSP) to determine the available resources of an ATM network. VF is a relative measure of Cell Rate Margin (CRM) normalized by the variance of the aggregate cell rate on the link.

Video Streaming
Video Streaming refers to transferring video data such that it can be processed as a steady and continuous stream over the network. With streaming, the client browser or plug-in can start displaying the multimedia data before the entire file has been transmitted. Video streaming technology is developed based on 2 key technologies, the video coding technology and scalable video distribution technology.

VID: VLAN ID
VLAN ID(VID) is the identification of the VLAN, which is defined by the standard IEEE 802.1Q. VID has 12 bits and allows the identification of 4096 VLANs.

VIP: Virtual IP
A virtual IP address (VIP) is an IP address that is not connected to a specific computer or network interface card (NIC) on a computer. Incoming packets are sent to the VIP address, but all packets travel through real network interfaces. VIPs are mostly used for connection redundancy; a VIP address may still be available if a computer or NIC fails because an alternative computer or NIC replies to connections. An example of of a virtual IP address is a Loopback (circuitless IP address) as the IP address is not associated with any one particular interface (or circuit) on the host or route.

Virtual Connection
Virtual Collocation may means the following: 1) an interconnection agreement where one telephone company owns, installs and maintains equipment to connect networks at another telephone company's request. 2) a logic connection between end users that has a defined route and endpoints in ATM network.

Virtual Path
Virtual Path, a term of ATM networing, refers to the logical grouping of virtual circuits that connect two sites.

Virtual Ring
Virtual Ring, a concept in an Source-Route Bridging (SRB) algorithm based network such as Token Ring, refers to logically connected two or more physical rings either locally or remotely. The concept of virtual rings can be expanded across router boundaries.

Virtual Route
Virtual Route, a conept in SNA network, refers to a logical connection between subarea nodes that is physically realized as a particular explicit route.

Virtual Subnet
Virtual Subnet refers to a logical grouping of devices that share a common Layer 3 subnet.

Virtual Trunk
Virtual Trunk(VT), a conceptin ATM network, is a virtual path connection setup by the network for reducing connection awareness at the transit nodes. A virtual trunk is considered as a connection by the network supporting it (the VP network), and as a logical trunk by the connections supported. VT has the following characteristics: address space containing only one VPI and all VCIs underneath, bandwidth that is rate limited by hardware (VI), and ownership by a controller that uses it to interface to another peer controller.

VLAN: Virtual LAN
Virtual LAN (VLAN) refers to a logical network in which a group of devices on one or more LANs that are configured so that they can communicate as if they were attached to the same wire, when in fact they are located on a number of different LAN segments. Because VLANs are based on logical, instead of physical, connections, they are very flexible for user/host management, bandwidth allocation and resource optimization.

VLI: Virtual LAN Internetwork
Virtual LAN Internetwork(VLI) is an interconnected networks composed of VLANs.

VLSM: Variable-length Subnet Mask
Variable-length Subnet Mask(VLSM) refers to the capability to specify a different subnet mask for the same network number on different subnets. VLSM can help optimize available address space.

VNC: Virtual Network Computing
Virtual Network Computing (VNC) is a desktop sharing system which uses the RFB (Remote FrameBuffer) protocol to remotely control another computer. It transmits the keyboard presses and mouse clicks from one computer to another relaying the screen updates back in the other direction, over a network.

VoATM Dial Peer
VoATM Dial Peer refers to the dial peer connected via an ATM network. A dial peer, also known as an addressable call endpoint, is a device that can originate or receive a call over a network.

VoATM: Voice over ATM
Voice over ATM(VoATM) refers to the technology enables a router to carry voice traffic (for example, telephone calls and faxes) over an ATM network. When sending voice traffic over ATM, the voice traffic is encapsulated using a special AAL5 encapsulation for multiplexed voice.

VoD: Video on Demand
Video on Demand(VoD) is a service using video compression to supply video programs to viewers when requested via ISDN or cable.

VoFR Dial Peer
VoFR Dial Peer refers to the dial peer connected via a Frame Relay network. A dial peer, also known as an addressable call endpoint, is a device that can originate or receive a call over a network.

VoFR: Voice over Frame Relay
Voice over Frame Relay(VoFR) refers to the technology that enables a router to carry voice traffic (for example, telephone calls and faxes) over a Frame Relay network. When sending voice traffic over Frame Relay, the voice traffic is segmented and encapsulated for transit across the Frame Relay network using FRF.12 encapsulation.

VoHDLC Dial Peer
VoHDLC Dial Peer is the dial peer connected via an HDLC network. A dial peer, also known as an addressable call endpoint, is a device that can originate or receive a call over a network.

VoHDLC: Voice over HDLC
Voice over HDLC (VoHDLC) refers to the technology that enables a router to carry live voice traffic (for example, telephone calls and faxes) back-to-back to a second router over a HDLC-based serial line.

VoIP Dial Peer
VoIP Dial Peer refers to the dial peer connected via a packet network; in the case of Voice over IP, this is an IP network. A dial peer, also known as an addressable call endpoint, is a device that can originate or receive a call over a network.

VoIP: Voice onver IP
Voice over IP (VOIP) refers to a group of technologies that use the Internet Protocol (IP) to transmit voice as packets over an IP network. Using VOIP protocols, voice communications can be achieved on any IP network regardless it is Internet, Intranets or Local Area Networks (LAN). In a VOIP enabled network, the voice signal is digitized, compressed and converted to IP packets and then transmitted over the IP network. VOIP signaling protocols are used to set up and tear down calls, carry information required to locate users and negotiate capabilities. The key benefits of Internet telephony (voice over IP) are the very low cost, the integration of data, voice and video on one network, the new services created on the converged network and simplified management of end user and terminals.

Vortal: Vertical Industry Portal
Vertical Industry Portal (Vortal) is a portal Web site that provides information and resources for a particular industry. Vortal is geared toward a specific niche audience with focused contents such as news, industry articles and analysis, whitepapers etc.

VP: Virtual Path
Virtual Path(VP) is one of two types of ATM circuits identified by a Virtual Path Identifier (VPI). A virtual path is a bundle of virtual channels, all of which are switched transparently across an ATM network based on a common VPI.

VPC: Virtual Path Connection
Virtual Path Connection(VPC), a concept in an ATM network, refers to the grouping of Virtual Channel Connections (VCCs) that share one or more contiguous Virtual Path Link (VPL).

VPDN: Virtual Private Dial-up Network
Virtual Private Dial-up Network(VPDN), also known as virtual private dial network, is a network that extends remote access to a private network using a shared infrastructure. VPDNs use Layer 2 tunnel technologies (L2F, L2TP, and PPTP) to extend the Layer 2 and higher parts of the network connection from a remote user across an ISP network to a private network. VPDNs are a cost effective method of establishing a long distance, point-to-point connection between remote dial users and a private network.

VPI: Virtual Path Identifier
Virtual Path Identifier (VPI) is a routing label used in the Asynchronous Transfer Mode (ATM) header. The VPI, together with the Virtual Channel Identifier (VCI), identifies the next destination of a cell as it passes through a series of ATM switches on its way to its destination. VPI field has 8 to 12 bits: 8 in the case of user-network interface and 12 in the case of network-network interface. The 4 extra bits in the network-network interface allows support for an expanded number of VPC internal to the network, which can be used for network management. A VPI of 0 indicates that this PVC is a virtual channel connection (VCC). A nonzero value indicates that this is a virtual path connection (VPC).

VPL: Virtual Path Link
Virtual Path Link (VPL) refers to a group of unidirectional Virtual Channel Links (VCLs) with the same end points. Grouping VCLs into VPLs reduces the number of connections to be managed, thereby decreasing network control overhead and cost. A Virtual Path Connection (VPC) is made up of one or more VPLs.

VPLS: Virtual Private LAN Service
Virtual Private LAN Service (VPLS) is an MPLS application defined by IETF. It allows geographically dispersed sites to share an ethernet broadcast domain by connecting each site to an MPLS-based network, as if they were in the same local area network (LAN). The wide area network (WAN) and metropolitan area network (MAN) become transparent to all customer locations. Ethernet VPN, based on VLPS and MPLS, provides more benefits than other alternative layer 2 or 3 VPN technologies.

VPN: Virtual Private Network
Virtual Private Network (VPN) refers to simulating a private network over the public Internet by encrypting communications between the two private end-points. This provides the same connectivity , QOS and privacy you would find on a typical private network.

VRB: Virtual Ring Buffer
Virtual Ring Buffer (VRB) is an implementation of a character FIFO ring buffer. It provides direct access to the buffer so the calling program can construct output data in place, or parse input data in place, without the extra step of copying data to or from a calling program provided buffer area. In order to facilitate this direct access, VRB makes sure that all references to buffer locations for either output or input is always a single contiguous block of memory so that the calling program does not have to deal with split buffer spaces every time the cycling of data reaches the end of the buffer and wraps around to the beginning. Thus, the calling program is free to use any number of tools available which do not have to be aware that they are operating directly in a ring buffer.

VRF: VPN Routing/Forwarding
VPN Routing/Forwarding (VRF) is an instance which is associated with a different virtual router, thus isolating each customers routing table from each other as well as from the providers (default) route table. A VPN instance consists of an IP routing table, a derived forwarding table, a set of interfaces that use the forwarding table, and a set of rules and routing protocols that determine what goes into the forwarding table.

VS/VD: Virtual Source/Virtual Destination
Virtual Source/Virtual Destination (VS/VD) is a feature in the ATM Available Bit Rate(ABR) service. The VS/VD option allows a switch to divide an end-to-end ABR connection into separately controlled ABR segments by acting like a destination on one segment, and like a source on the other.

VSA: Vendor-Specific Attribute
Vendor-Specific Attribute(VSA), a feature in the RADIUS, refers to the attribute that has been implemented by a particular vendor. It uses the attribute Vendor-Specific to encapsulate the resulting AV pair: essentially, Vendor-Specific = protocol:attribute = value.

VSI Master: Virtual Switch Interface Master
A Virtual Switch Interface (VSI) master process implementing the master side of the VSI protocol in a VSI controller. Sometimes the whole VSI controller might be referred to as a VSI Master. In other words, VSI master is a device that controls a VSI switch, for example, a VSI label switch controller, a process implementing the master side of the VSI protocol.

VSI: Virtual Switch Interface
Virtual Switch Interface (VSI) is a protocol used to control a Wide Area Network switch, for networking applications, such as MultiProtocol Label Switching (MPLS) or PNNI routing. With VSI, external controllers are used to control the switch for applications not supported by the traditional WAN switch set of routing protocols known as AutoRoute. The VSI protocol is a master/slave protocol. The master part of the VSI protocol runs on the SES PNNI controller for PNNI networking. The slave part of the VSI protocol runs on the BXMs on the BPX.

VSND: Virtual Source/Virtual Destination
Virtual Source/Virtual Destination (VSND) ia an ATM ABR connection that may be divided into two or more separately controlled ABR segments. Each ABR control segment, except the first, is sourced by a virtual source. A virtual source implements the behavior of an ABR source endpoint. Backward RM-cells received by a virtual source are removed from the connection. Each ABR control segment, except the last, is terminated by a virtual destination. A virtual destination assumes the behavior of an ABR destination endpoint. Forward RM-cells received by a virtual destination are turned around and not forwarded to the next segment of the connection.

VT: Virtual Terminal
Virtual terminal (VT) is an application service that allows host terminals on a multi-user network to interact with other hosts regardless of terminal type and characteristics. VT allows remote log-on by local area network managers for the purpose of management. VT allows users to access information from another host processor for transaction processing.

VTAM: Virtual Telecommunications Access Method
Virtual Telecommunications Access Method (VTAM) is an IBM API that controls communications between Logic Units (LUs) in an SNA network. VTAM controls data transmission between channel-attached devices and performs routing functions. VTAM supports several network protocols, including SDLC and Token Ring.

VT-n: Virtual Tributary Level n
Virtual Tributary Level n (VT-n) is a SONET format for mapping a lower-rate signal into a SONET payload. For example, VT-1.5 is used to transport a DS-1 signal.

Vty: Virtual TeletYpe
Virtual TeletYpe (VTY) is an interface that allows user to connect to the daemon via the telnet protocol.

VWP: Virtual Wavelength Path
Virtual Wavelength Path (VWP) is a group of one or more channels between source and destination nodes. The term virtual indicates that the signal path can actually travel on different physical wavelengths throughout the network. All channels of the VWP transit the same path through the network.